1. Field of the Invention
The present invention relates to a fuel injection type internal combustion engine.
2. Description of the Related Art
A fuel injection type internal combustion engine is known in which the piston has a cavity formed on the top face thereof, and a fuel injector having a plurality of nozzle bores is mounted on the cylinder head. In this engine, fuel, for example, methanol, is injected in all radial directions from the nozzle bores of the fuel injector and ignited by a spark plug.
As is well known to a person skilled in the art, in order to improve the thermal efficiency of the engine, preferably the compression ratio of the engine is increased, but if the compression ratio is increased in the above-mentioned engine, knocking occurs. Consequently, since it is impossible to increase the compression ratio, it is difficult to improve the thermal efficiency.